Edwards nEXT730 - Page 113

B8J200880_E - Fault finding
Page 112
Fault The pump is very noisy or there is excessive vibration or both
Cause
The pump rotational speed is the same as the resonant frequency of the attached
system.
Cause The vibration is being transmitted from the rotary backing pump.
Cause The noise is irregular and getting progressively worse.
Cause The pump is making a constant high pitched noise.
Fault No serial comms
Cause No electrical supply, loss of serial link.
Cause Slide switch is not in the correct position for RS232 or RS485.
Cause Incorrect baud rate and node address.
Cause Check that the red light is not on or flashing.
Fault Fail signal or standby signal not working
Cause The serial enable line is inactive.
Remedy
▪ Remove the pump from the system and test the ultimate pressure of the
pump alone (refer to Table: Technical data nEXT730, nEXT930 and Table:
Technical data nEXT1230).
▪ If inlet pressure is poor, check the pump for contamination and refer to Table:
Technical data nEXT730, nEXT930 and Table: Technical data nEXT1230.
▪ Leak test the pump. If the leak rate > 1x10
-7
mbar l s
-1
(1x10
-5
Pa l s
-1
),
contact the supplier or us.
Remedy Change the natural frequency of the system or isolate the pump using flexible
bellows.
Remedy Fit flexible bellows or a vibration isolator in the backing line.
Remedy There is a defective bearing. Contact the supplier or us.
Remedy The rotor is out of balance. Contact the supplier or us.
Remedy Check that the electrical supply is on, that the serial link is connected and that the
serial enable line is active.
Remedy
▪ Check that the electrical supply is on, that the serial link is connected and
that the serial enable line is active.
▪ Left for RS485, right for RS232.
▪ Right for parallel control and monitoring.
Remedy Check baud rate and, if operating in multi-drop mode, the node address matches
those of the pump.
Remedy If LED is on, perform the checks against the red alarm LED symptoms
Remedy Must be disconnected or driven high for use of standby and fail lines.
Cause The inlet pressure is poor.